Honda CB750 Sandcast

Here we go! Restoring 576/748

Wayne · 180 · 71149

kp

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Yep it's factory. Even new ones have it but the why question is a good one. Does Chris R have any idea.
Yabba Dabba KP


ashimotok0

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I don't think it is epoxy - it dissolves too easily in solvent. I believe it is standard and for sound deadening, The covers are really thin and may tend to 'ring'  due to vibration of the motor. I can't be sure of that though. The clutch cover on the CB750K7 (tougher clutch with Gold Wing 'B' plate fitted) is much thicker and does not have the 'cementy' coating, presumably because it's thickness prevents it from 'ringing'. Just my theory ChrisR may chip in and prove me wrong though  ;D.

Whey hey - just noticed todays posts have taken away my 'Newbie' pesky status!!  :)

Cheers

Ash
« Last Edit: November 23, 2010, 01:40:48 pm by ashimotok0 »


markb

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I've seen it on the inside of the points covers too.  My vote is it's epoxy and it's for sound deadening.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


ashimotok0

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The only reason I thought it may not be epoxy is that I removed the chrome palting  from a clutch cover electrolytically and the coating just disintigrated. Could well be wrong though.

cheers

ash


hondasan

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As suggested, seems likely it is for sound deadening. Inetrestingly, there are TWO types of chrome clutch cover - some are made of a thicker gauge steel than the others (like they weigh near twice as much as the "thinner" ones!), but have never been able to pin it down to thick early, thin late, or otherwise. Must look in my box of leftovers and see if only the thin ones have the inner coating).

Cheers - Chris R.
Chris R.
302/338


Wayne

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Seems to be a theme with this bike. For every good I find a bad. One oil line is in pretty decent shape. The other is frayed quite badly in one area. The oil tank is self explanatory. Someone brazed a fitting in for an oil temp sending unit. This section could easily be cut out and with a little tig magic and some work no-one would know there was a repair made...except me. I'll be keeping my eyes open for a good tank.

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markb

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Wayne,
Seems like the way it goes with me too, good news, bad news.  Interesting about that fitting.  With the breather holes I wouldn't there would be any pressure in the oil tank.  Maybe I'm wrong but I thought the oil fed by gravity to the pump and then circulated back to the tank.  The experts can chime in here but I think the earlier tanks were a little different, flatter, thinner maybe?
Nice to see you making progress.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


Wayne

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Here's a shot of my engine "dot". As you can see it's blue/green. The bike was Red until someone painted it the awful brown it is now. (The last owner told me on the weekend it is GM Autumn Brown) I have another name for it!  ;)

For what it's worth, here's my Green Dot.



Got the carb's off. Nothing too noteworthy here I don't think.



Pulled a bowl off for a peek.



« Last Edit: November 24, 2010, 08:11:26 pm by Wayne »
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Wayne

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Got all of the electrical off the bike including the wiring harness. It's an -0400 harness and only 3 connectors have been compromised. (cut) The rest are all original but the clear covers are as hard as a rock for the most part. I know these can be replaced. As well the black sheathing is split and hard. I can't decide whether to just get the superceded harness and have everything nice and new, or restore this old girl. I guess I could always cut the extra wire off on a new harness, take my -0400 tag and make it looks like it belongs there or have a tag made up and make a completely new "forgery".  ;) I have a while to weigh my options and gather member feedback.



Hard to see but there are 2 blue crimp connectors and one cut wire at the ignition switch.

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hondasan

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Always good to keep the original if at all possible - I think you will find that the "050" looms are different in that they have two extra wires into the headlight for those markets that run a pilot light in the headlight. Can't be seen when fitted, but YOU will know!

As well as the problems you have mentioned with yours, I have had several (040, and 050) where the square block connectors are partially melted, usually at the rectifier connection where poor contacts have caused overheating - Any one found a source of the early "non latch" type connectors?

Cheers - Chris R.
Chris R.
302/338


Riccardo

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Waine,

i've used for my 2 restore 2 new OEM wire haress:one works great and one so so, the rear parking light when is ON also the engine can start ??? ??? ???

As soon i've time i'll search the defect. :'(

My suggestion for You is:
use the your wire harness, restore it with http://www.vintageconnections.com/
In this site you can find the old look for your connections and lines. :)

Ciao
Riccardo
Your Italian friend.
737/940 Restored
1081/1362 Preserved
1256/665 Restored - ex Owner: Chris R.
10253/10315 (K0) Next project
1969 - Kawasaki H1 Mach III low ign cover - Restored
1969 - Kawasaki H1 Mach III high ign cover - Restored
1971 - Kawasaki H1A - Restored
1973 - Kawasaki H1D - Preserved
1973 - Kawasaki Z1 Blackhead - Restored
1971 - Norton Commando SS - Preserved
1978 - Honda CBX - Unmolested Museum Quality
1988 - Honda CB 400SS - Unmolested
1997 - BMW R80 GS Basic - blue frame - Museum Quality
2007 - BMW HP2 Megamoto - blue frame - New


Wayne

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Thanks for the info Riccardo / Chris. Perhaps best to see what I can do with this harness.
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ashimotok0

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I think my original K0 wiring loom looks superb now and my wiring loom looked pretty bad to start with from a UK bike 40 years old. I used

http://www.vintageconnections.com Thanks to post from 'Hondaman' for non-latch connectors, bullets and more importantly the sleeving. UK people - Don't buy the ones off Ebay - the bullets  are the wrong size and the sleeving is non-glossy and crap. You can clean up any plain brass connectors after degreasing with alcohol using a 50/50 mix of coke (phosphoric acid) and lemon juice (citric acid) and replate any tinned connectors with the tinning solution used in PCB manufacture (sadly the modern less toxic stuff isn't a patch on the old stuff but I still have some old stuff). I even found my coloured wires came with small printed wording 'Sumitomo 1969' Cool! The rule is to use the proper non-adhesive loom tape -NO HEATSHRINK (apart from soldered splices on repairs inside the loom) and only a few inches of black insulation tape for the ends of the non-adhesive wrapping. Any repairs can be made using wires from any scrap SOHC loom and you can turn round the red glass woven sleeving so that the bit non-faded from under the black tape is where the exposed part is normally.

BTW - may be old hat to everyone but the rectifier diodes on the 3-phase recifier can be removed individually and replaced with ones from another scrap rectifier because they de-solder from the connector plate. Be careful though as one plate is common anode and one common cathode bodies.

Just my 2 cents/pence worth - shoot me down in flames if you don't agree  ;D - I am more than happy with it.

BTW Anyone contemplating a repro Honda one beware this from CMS customer feedback!
________________________________________________________________________________________________________
 
1 of 1 people found the following review useful:  
  wire harness, Thursday, April 16, 2009
Reviewer: Juergen Schroeder  
In general this wire harness looks as good as the original one and comes with all the connections necessary. Although, lately, i.e. one year of my purchase I had problems with the electricity from the ignition lock. It turned out that the black mass wires inside the harness (thus invisible from the outside) were only rolled around each other and not soldered!!! The producer of the wire harness should be told to solder these connections and he will spare people hours of endless search and despair.  


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« Last Edit: November 26, 2010, 02:18:55 pm by ashimotok0 »


1941wld

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Hi Wayne,
This was the harness we were talking about. Sorry I did not post this before the end of auction, I tried to get this but I missed.
It is the 300-040
http://cgi.ebay.com/ebaymotors/69-70-Honda-CB-750-Sandcast-Wiring-Harness-Switches-/290497993007?pt=Motorcycles_Parts_Accessories&hash=item43a307992f


kp

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I think my original K0 wiring loom looks superb now and my wiring loom looked pretty bad to start with from a UK bike 40 years old. I used

http://www.vintageconnections.com Thanks to post from 'Hondaman' for non-latch connectors, bullets and more importantly the sleeving. UK people - Don't buy the ones off Ebay - the bullets  are the wrong size and the sleeving is non-glossy and crap. You can clean up any plain brass connectors after degreasing with alcohol using a 50/50 mix of coke (phosphoric acid) and lemon juice (citric acid) and replate any tinned connectors with the tinning solution used in PCB manufacture (sadly the modern less toxic stuff isn't a patch on the old stuff but I still have some old stuff). I even found my coloured wires came with small printed wording 'Sumitomo 1969' Cool! The rule is to use the proper non-adhesive loom tape -NO HEATSHRINK (apart from soldered splices on repairs inside the loom) and only a few inches of black insulation tape for the ends of the non-adhesive wrapping. Any repairs can be made using wires from any scrap SOHC loom and you can turn round the red glass woven sleeving so that the bit non-faded from under the black tape is where the exposed part is normally.

BTW - may be old hat to everyone but the rectifier diodes on the 3-phase recifier can be removed individually and replaced with ones from another scrap rectifier because they de-solder from the connector plate. Be careful though as one plate is common anode and one common cathode bodies.

Just my 2 cents/pence worth - shoot me down in flames if you don't agree  ;D - I am more than happy with it.


They'll be no one shooting you down in flames Ash. That's a great post. I learnt something from it ie: you can turn round the red glass woven sleeving so that the bit non-faded from under the black tape is where the exposed part is normally. Good stuff  8) KP
Yabba Dabba KP